Pulse laser systems at the present stage of the art are well known, but are erratic and unreliable in nature. Systems tend to be critical in alignment and dimensioning and even when well aligned are erratic in producing a reliable and expected level of performance day after day. Thus, in the prior art there have not been available reliable commercial pulse laser systems that reproduce output pulses of similar output intensity profiles from shot to shot in the absence of critical short range calibration and alignment under ideal operating conditions.
It is known in the art that spurious oscillations may be induced in laser systems thereby decreasing reliability and usefulness. Thus, U.S. Pat. No. 3,682,178, E. B. Treacy, Dec. 14, 1971; No. 3,808,554, M. Lax et al., Apr. 30, 1974; and No. 3,715,685, Ed Gordon et al., Feb. 6, 1973 provide modified reflective paths operable with reflecting means to suppress unwanted oscillation modes that interfere with reliability and performance.
Also it is known that spurious secondary and satellite pulses interfere with reliability and performance. Thus, W. D. Fountain et al. in U.S. Pat. No. 4,019,156, Apr. 19, 1977 provides for a combination of active and passive loss modulators within the optical cavity wherein the mode locking function is controlled by an active electro-optical modulator. However this system does not adequately eliminate the generation of unwanted secondary pulses and introduces the complexities of active filters.
It is therefore an object of the present system to improve the reliability of the pulse reproduction of a mode-locked laser system by elimination of satellite pulsing, thereby assuring that the output pulses are of a predetermined intensity profile.
It is a further object of the invention to provide a reliable pulse producing laser system without reliance upon expensive and critical electro-optical active filters, or other expensive lens systems requiring special lenses critical in construction and limited to operation at particular wavelengths.
A general object of the invention is to provide a simplified low cost system that is not critical in operation and that will be reliable in reproducing consistently output pulses of a predetermined intensity profile.
A more specific object of the invention is to make a mode-locked Nd:glass laser system reliable from shot to shot in emitting consistent output pulses of predetermined characteristics.
Another object of the invention is to produce in a similar manner an improved Ruby laser system.